Another good one would be "The Exchange" which is a local/regional video game, movie and music store. Buys/sells new and used. Look up on google maps for a location near you. They've never had a decent web site as each one is independently owned.

My best experience for selling a large collection of video games has been with Columbus Game Buyer. They offered me much better prices that the other video game stores and even made offers on some of my older games and consoles that Gamestop wasn't interested in. The only thing is they don't have a store (I think they sell online or something), but they do local pickups and they pay cash. Really nice guys and I would highly recommend them.